The peacemakers within themselves are they who having stilled all disturbances of their spirits, having subjected them to reason, have overcome their carnal desires, and become the kingdom of God. There all things are so disposed, that that which is most chief and excellent in man, governs those parts which we have in common with the brutes, though they struggle against it; nay even that in man which is excellent is subjected to a yet greater, namely, the very Truth, the Son of God. For it would not be able to govern what is inferior to it, if it were not subject to what is above it. And this is the peace which is given on earth to men of good will.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Serm. in Mont., i, 2